The present invention relates generally to the field of gas turbine combustors and, more particularly, to a system and method for supporting fuel nozzles in a gas turbine combustor utilizing a support plate.
A gas turbine combustor has an-associated fuel nozzle assembly. The fuel nozzle assembly typically includes a number of fuel nozzles cantilevered off of a fuel nozzle supporting housing. Each fuel nozzle has an associated swirler vane and shroud that facilitates the mixing of air with fuel from the fuel nozzle before entering the combustor.
The shrouds of the fuel nozzles need to fit within holes in a baseplate of the combustor housing in a manner that prevents large gaps between the shrouds and the baseplate. However, because there are typically a number of fuel nozzles that need to be installed and since the fuel nozzle assembly is installed as a single unit within the combustor housing (i.e., a blind assembly), there is usually not a good fit between the ends of the shrouds and the holes in the baseplate. The baseplate provides minimal support to the ends of the fuel nozzles. This causes each individual fuel nozzle to be susceptible to side-to-side vibration. Vibration of fuel nozzles in a gas turbine combustor is detrimental because it increases the likelihood of failure in addition to decreasing the life of the fuel nozzles.
According to an embodiment of the invention, a fuel nozzle assembly includes a plurality of fuel nozzles coupled to a fuel nozzle support housing proximate an upstream end of each fuel nozzle, a plurality of swirler vanes rigidly coupled to respective fuel nozzles proximate an intermediate portion of the fuel nozzle, a plurality of shrouds rigidly coupled to respective swirler vanes, each shroud having an upstream end adjacent the intermediate portion of the fuel nozzle and a downstream end, and a support plate rigidly coupled to the plurality of shrouds proximate an intermediate portion of each of the shrouds. The support plate has a perimeter approximately equal to an inside perimeter of a housing of a combustor.
Embodiments of the invention provide a number of technical advantages. The invention may include all, some, or none of these advantages. The invention provides a support plate that couples a plurality of fuel nozzles together and structural support in such a manner that minimizes detrimental vibration of the fuel nozzles. Without this structural support each fuel nozzle would be basically cantilevered off the support housing. The fuel nozzles would receive some support from the engagement of the shroud into the baseplate but this support would be minimal because the baseplate is not a rigid structure. Each fuel nozzle""s fundamental mode of vibration is elevated to a higher natural frequency, significantly stiffening each fuel nozzle with the present invention helps support and dampens that vibration so that more energy is required to excite each fuel nozzle. The fuel nozzle support base plate helps to align during assembly and operation the fuel nozzles within the combustor housing of a gas turbine combustor as well as to facilitate alignment between the fuel nozzle shrouds and combustor housing baseplate. This helps to prevent loss of cooling air, heat distortion, and potential vortices.